Matter is anything that has mass and occupies space. It exists mainly in three states: solid, liquid and gas. A fourth state, plasma, and a fifth, Bose-Einstein condensate, are also recognised. The properties of each state are common exam questions.
Three Main States
- Solid: fixed shape and fixed volume; particles are tightly packed.
- Liquid: fixed volume but no fixed shape; takes the shape of its container.
- Gas: neither fixed shape nor fixed volume; particles move freely.
Particle Arrangement
- In solids, particles vibrate but stay in place; forces between them are strong.
- In liquids, particles can slide past each other.
- In gases, particles are far apart and move fast.
- Compressibility is highest in gases and lowest in solids.
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Change of State
- Melting: solid to liquid; freezing: liquid to solid.
- Evaporation / boiling: liquid to gas; condensation: gas to liquid.
- Sublimation: solid directly to gas (example: camphor, naphthalene).
- Temperature stays constant during a change of state (latent heat).
Other States
- Plasma is a hot, ionised gas found in stars and the Sun.
- Bose-Einstein condensate (BEC) forms at extremely low temperatures.
Quick Revision Points
- Three main states: solid, liquid, gas.
- Solid = fixed shape and volume.
- Liquid = fixed volume, no fixed shape.
- Gas = no fixed shape or volume; most compressible.
- Sublimation: solid to gas directly (camphor).
- Plasma is found in stars and the Sun.
- Heat used in change of state is latent heat.